1. Field of the Invention
The present invention relates to an apparatus of the type used for helically assembling filaments or elongated flexible elements together to form a cable or the like.
2. Description of the Prior Art
U.S. Pat. No. 4,709,542 issued to Krafft on Dec. 1, 1987, discloses a stranding apparatus adapted to form stranded cables of infinite lengths.
More specifically, Krafft discloses a cable assembly apparatus having a rotating shaft which is provided with two integral supply reels which are respectively adapted to receive thereon a group of wire elements. The flyer assembly rotates around the supply reels for unwinding the groups of wire elements therefrom. The flyer assembly is rotated in the same direction as the two integral supply reels but at a speed which causes the wire elements to be unwound from the supply reels. A drive motor is directly connected to the rotating shaft for driving the integral supply reels. The flyer assembly is connected to the same drive motor but through a variable diameter pulley assembly so that the rotational speed of the flyer assembly is adjustable with respect to that of the integral supply reels. The apparatus further comprises a gathering assembly which is mounted for rotation with the flyer assembly for gathering and twisting the individual wire elements together or over a core element to form a cable. A take-up reel is disposed downstream from the gathering assembly to receive thereon the finished cable coming out from the center of the rotating shaft. A motor is coupled to the take-up reel to enable the same to be operated to draw the cable from the gathering assembly. The motor of the take-up reel may be adjusted to maintain a desired amount of tension in the cable to enhance the quality of the finished cable. However, it is the rates of rotation of the integral supply reels and of the flyer assembly which control the rate of production of the cable and thus the tension which is applied to the cable does not change the rate at which the cable is produced. Indeed, an increase of the rotational speed of the take-up reel does not change the rotational speed of the integral supply reels as the same are not allowed to freely rotate on the rotating shaft thereof. Accordingly, in order to obtain a desired length of twist per unit length of cable, the rotational speed of the flyer assembly must be adjusted relative to the rotational speed of the integral supply reels.
It is believed that the apparatus of the above described patent never gained commercial acceptance as the helical pitch of the final product and the amount of tension in each supply wire were overly difficult to control.
FIG. 8 illustrates a conventional apparatus 410 used in steel industries to helically assemble a plurality of individual strands together about a central core to form a steel cable.
The apparatus 410 generally comprises a rotatable tube 412 mounted to a frame structure 414 for rotation about a central axis, and a plurality of supply spools 416, 418, 420 and 422 mounted for rotation about respective transversal axes. The supply spools 416, 418, 420 and 422 have respective strands 424, 426, 428 and 430 wound thereon. A capstan 432 is disposed downstream of the tube 412 for pulling the strands 424, 426, 428 and 430 out of a matrice 434 provided at the downstream end of the tube 412 for helically assembling the individual strands 424, 426 and 428 together about the central strand 430. The spools 418, 420 and 422, which are disposed within the tube 412, are supported by respective non-rotatable cradles 436, whereas the spool 416, which is disposed upstream of the tube 412, may be supported by any suitable support structure (not shown). The tube 412 defines at an upstream end thereof a first central passage 438 for allowing the strand 424 of the supply spool 416 to access the interior of the tube 412. Furthermore, the tube 412 defines at a downstream end thereof a second central passage 440 for allowing the strand 430 of the spool 422 to pass through the apparatus 410 along the central axis without being twisted to form the central core of the cable. Pulleys 442 connected to the tube 412 are provided between the spools 416418, 420 and 422 along the central axis for engaging the strands 424, 426 and 428 before the same be directed to other pulleys 444 mounted to the external surface of the tube 412.
In operation, the capstan 432 is activated to advance strands 424, 426, 428 and 430 through the apparatus 410, while the tube 412 is driven in rotation to cause the strands 424, 426 and 428 to rotate about the central strand 430. It is noted that the strands 424, 426 and 428 are twisted onto themselves as they engage respective pulleys 442 and are untwisted when they leave the tube 412, i.e. when they pass over the last pulleys 444 disposed at the downstream end of the tube 412, thereby ensuring that each individual strand be untwisted in the assembled product. Finally, the strands 424, 426 and 428 are helically assembled together on the central strand 430 as they return to the central axis within the matrice 434. As seen in FIG. 8, the assembled product may be wound on a take-up spool 446 disposed downstream of the capstan 432.
Basically, the above stranding apparatus 410 is intended for producing steel cables formed of a plurality of strands helically assembled on a central core and is thus not well adapted for manufacturing twisted pair cables, such as those used for transmitting messages.
FIG. 9 illustrates a conventional apparatus 510 for manufacturing twisted pair cables, i.e. cables composed of two strands helically assembled together about a central axis. Such an apparatus generally comprises a main flyer 512 adapted to impart a double twist to a pair of strands 514 and 516 emanating from a matrice 518. The two strands 514 and 516 are wound on respective supply spools 520, 522 and directed onto two distinct rotating flyers 524 and 526 which are driven in rotation so as to suppress the twist which is imparted to the strands 514 and 516 in order to ensure that each strand 514, 516 be not twisted onto itself in the assembled product. The assembled product may be received on a take-up spool 528 disposed inside of an envelope defined by the rotational movement of the main flyer 512.
Although the above apparatus 510 performs satisfactorily in many applications, it has been found that there is a need for a simpler and less expensive apparatus which does not necessitate the utilisation of three flyers.
It is therefore an aim of the present invention to provide an apparatus for helically assembling filaments about a common axis or, alternatively, over a core element to produce a cable.
It is also an aim of the present invention to provide an apparatus which is adapted to helically assemble a pair of filaments about a central axis.
It is a still further aim of the present invention to provide such an apparatus which is adapted to produce cables or the like having substantially uniform helical pitches throughout the length thereof.
It is a still further aim of the present invention to provide such an apparatus which is capable of adjusting an controlling the amount of tension in each individual filament passing through the apparatus.
It is a still further aim of the present invention to provide such an apparatus which is provided with removable supply spools.
Therefore, in accordance with the present invention, there is provided a supply spool and flyer assembly for an apparatus adapted to helically assemble a pair of filaments about a central axis as said filaments are passed through a gathering point, said supply spool and flyer assembly comprising first supply spooling means having a first filament wound thereon, flyer means disposed between said first supply spooling means and the gathering point, said flyer means being mounted on axle means for rotation therewith about said central axis, said flyer means being provided with first guide means for guiding said first filament along said flyer means, and second supply spooling means disposed within an envelope defined by a rotational movement of said flyer means about said central axis, said second supply spooling means having a second filament wound thereon, said axle means being provided, downstream of said second supply spooling means, with second guide means configured to cause said second filament to rotate with said axle means about said central axis as said second filament is moved through said second guide means.
Also in accordance with the present invention, there is provided a supply spool and flyer assembly for an apparatus adapted to helically assemble a pair of elongated flexible elements about a central axis as said elongated flexible elements are passed through a gathering point, said supply spool and flyer assembly comprising first supply spooling means having a first elongated flexible element wound thereon, flyer means disposed downstream of said first supply spooling means and upstream of the gathering point, said flyer means being mounted on axle means for rotation therewith about said central axis and defining a first guide path for said first elongated flexible element, whereby rotation of said flyer means will cause said first elongated flexible element to rotate about said central axis as said first elongated flexible element is moved through said first guide path, and second supply spooling means disposed within an envelope defined by a rotational movement of said flyer means about said central axis, said second supply spooling means having a second elongated flexible element wound thereon, said second elongated flexible element being moved through a second guide path extending through said axle means and to the gathering point so as to deviate off-axis said second elongated flexible element at a location comprised between said envelope and the gathering point, whereby rotation of said axle means will cause said second elongated flexible element to rotate about said central axis such that when said first and second elongated flexible elements return to the central axis at the gathering point, said first and second elongated flexible elements will be helically assembled together.
Also in accordance with the present invention, there is provided an apparatus for helically assembling elongated flexible elements about a common axis to form a product, comprising at least two supply spooling means having respective elongated flexible elements wound thereon, flyer means adapted to cause said elongated flexible elements to rotate about said common axis as said elongated flexible elements pass thereon, and a tension equaliser disposed between said flyer means and an element gathering point disposed outside of said flyer means, said tension equaliser being effective for equalising the tension in said elongated flexible elements before the same be helically assembled together at said element gathering point.
Also in accordance with the present invention, there is provided a helical pith control system for a stranding apparatus adapted to produce a stranded cable, comprising flyer means adapted to cause filaments passing thereon to rotate about a central axis, capstan means adapted to draw the filaments from said flyer means, said capstan means including a number of interchangeable capstan wheels of different diameters adapted to engage said filaments so as to impart an advancing speed to said filaments, said advancing speed being a direct function of the diameter of said interchangeable capstan wheels and of a rotation speed thereof, motor means for driving said flyer means and said capstan means at a predetermined speed ratio, whereby said interchangeable capstan wheels are selected according to a desired helical pith of a stranded cable to be manufactured.
Still in accordance with the present invention, there is provided a system for controlling the amount of tension in a filament being drawn off from a supply spooling means, comprising braking means for exerting an adjustable opposition to a rotation of said supply spooling means, clutch means adapted to generate a coupling torque for coupling said supply spooling means to driving means, and control means for adjusting the opposition of said braking means to the rotation of said supply spooling means so as to maintain a desired amount of tension in said filament, whereby when said coupling torque of said clutch means is less than said opposition exerted on said supply spooling means by said braking means, said clutch means slips thereby preventing said supply spooling means from being driven by said driving means, and when said opposition of said braking means becomes less than said coupling torque of said clutch means, said supply spooling means is driven by said driving means via said clutch means.
Still in accordance with the present invention, there is provided an apparatus for helically assembling individual elongated flexible elements about a common axis to form a product, comprising at least two independent supply spooling means mounted for rotation about an axis, each said supply spooling means having a single elongated flexible element wound thereon, flyer means mounted for rotation about said axis and around said supply spooling means, means for rotating said flyer means about said axis, said elongated flexible elements being directed from said supply spooling means to said flyer means and then to a gathering point wherein said elongated flexible elements are helically assembled about said axis according to a rotational movement of said flyer means, advancing means for advancing said elongated flexible elements through said apparatus, and a tension adjusting means adapted to independently act on said supply spooling means to maintain a desired amount of tension in each said elongated flexible element.
Also in accordance with the present invention, there is provided an apparatus for assembling at least one individual elongated flexible element on an advancing core to form a product, comprising at least one independent supply spooling means mounted for rotation about an axis, said supply spooling means having a single elongated flexible element wound thereon, flyer means mounted for rotation about said axis and around said supply spooling means, means for rotating said flyer means about said axis, said elongated flexible element being directed from said supply spooling means to said flyer means and then to a gathering point wherein said elongated flexible element is helically assembled around said core passing axially through said gathering point, advancing means for advancing said elongated flexible element and said core through said apparatus, and a tension adjusting means adapted to independently act on said supply spooling means to maintain a desired amount of tension in said elongated flexible element thereof.
Further in accordance with the present invention, there is provided an apparatus for helically assembling filament means about a common axis to form a product, comprising at least two supply spooling means mounted for rotation about an axis, each said supply spooling means having filament means wound thereon, flyer means mounted for rotation about said axis and outwardly of said supply spooling means, means for rotating said flyer means about said axis, said filament means being directed from said supply spooling means to said flyer means and then to a gathering point wherein said filament means are helically assembled about said axis according to the rotational movement of said flyer means, advancing means for pulling said filament means off said supply spooling means and for imparting an advancing speed to said filaments means through said apparatus, and means for controlling and adjusting the speed ratio between the advancing speed of said filament means and a rotational speed of said flyer means to achieve a substantially uniform number of rotations of said flyer means per unit of length of said product.
Still further in accordance with the present invention, there is provided an apparatus for helically assembling at least one filament means on an advancing core to form a product, comprising at least one supply spooling means mounted for rotation about an axis, said supply spooling means having filament means wound thereon, flyer means mounted for rotation about said axis and outwardly of said supply spooling means, means for rotating said flyer means about said axis, said filament means being directed from said supply spooling means to said flyer means and then to a gathering point wherein said filament means is helically assembled around said advancing core passing axially through said gathering point, advancing means for pulling said filament means off said supply spooling means and for imparting an advancing speed to said filament means and to said advancing core through said apparatus, and means for controlling and adjusting the speed ratio between the advancing speed of said filament means and a rotational speed of said flyer means to achieve a substantially uniform number of rotations of said flyer means per unit of length of said product.
Still further in accordance with the present invention, there is provided an apparatus for assembling filament means about a common axis, comprising a plurality of supply spool and flyer assemblies disposed in series, each said supply spool and flyer assembly including at least one supply spooling means mounted for rotation about an axis and a flyer means also mounted for rotation about said axis and outwardly of said supply spooling means, said at least one spooling means having filament means wound thereon, said filament means being directed from said supply spooling means to said flyer means, said flyer means of said plurality of supply spool and flyer assemblies being rotated substantially at a same speed and in a same direction, a gathering point for receiving said filament means from a downstream end of said plurality of supply spool and flyer assemblies, said filament means being assembled about said axis at said gathering point according to a rotational movement of said flyer means, advancing means for displacing forward said filament means through said plurality of supply spool and flyer assemblies and through said gathering point.
Still further in accordance with the present invention, there is provided an apparatus for assembling filaments means on an advancing core comprising a plurality of supply spool and flyer assemblies disposed in series, each said supply spool and flyer assembly including at least one supply spooling means mounted for rotation about an axis and a flyer means also mounted for rotation about said axis and outwardly of said supply spooling means, said spooling means having filament means wound thereon, said filament means being directed from said supply spooling means to said flyer means, said flyer means of said plurality of supply spool and flyer assemblies being rotated substantially at a same speed and in a same direction, a gathering point for receiving said filament means and said advancing core from a downstream end of said plurality of supply spool and flyer assemblies, said filament means being assembled around said advancing core at said gathering point according to a rotational movement of said flyer means, advancing means for displacing forward said filament means and said advancing core through said plurality of supply spool and flyer assemblies and through said gathering point.